Really bad service

In September 2023 I trade my car and the dealer cansel my subscription with matrix and in my new car ad a new matrix device where it was paid up for three years.. They still continue charging me for the old device I phoned I spoke to different consultants. And we're unable to assist. In February 2024 I send an email and they send me a form I had to complete. I send that form but still they continue phoning me about paying this device.Then I was given over to legal to deal with this. Currently I have a fully paid up device in my new car but access is denied to their app because I owe them money on a device I don't have. Money they wanting to deduct after phoning on various occasions and informing that I no longer use that tracker. I will not recommend them to anyone.